How To Use A Sealant Primer.

Optomise sealant adhesion.

As the most well respected supplier of silicone, polyurethane and MS polymer sealant in Ireland, we are regularly asked about suitable primers which can be used with any of our sealants. Sealant primers are optimised to increase the adhesion between the sealant, and the surface onto which the sealant is being applied.

We manufacture three different primers for use with sealants and sealant adhesives. These primers promote adhesion on non-porous materials such as plastics, ceramics and painted surfaces, porous materials such as brick, cement and other inorganic building materials, and finally other materials such as metals and plastic’s.

Let us now examine some of the basic tips which we suggest. First and foremost, in using any sealant, the surface must be clean and dry. Don’t listen to the suggestion that some sealants can be applied to damp or wet surfaces. It’s salesmen speak! What will stick to a damp surface? Very little, and certainly no known sealant!

Therefore, clean the surface with one of our cleaners or degreasers. Our Sales Depart men would be happy to suggest one. Next, and before the primer is applied, use a good quality masking tape to keep the joint free of excess primer, and protect areas where primer is not needed.

Next, open the bottle of primer, and pour some of it into a clean, metal container. We typically suggest this, as it prevents the primer in the supply bottle, from being contaminated. Some primers are very reactive, in particular, sensitive to moisture. Therefore, we suggest that the cap on the supply container, is replaced as soon as possible.

Depending on the substrate and application conditions, two different methods can be used to apply the primer. The preferred application is to dip a clean, dry, lint-free cloth into the primer and very gently, wipe a thin film onto the surface. For inaccessible areas and rough surfaces, apply the primer in a thin film with a clean brush.

Be mindful that over priming may cause adhesion loss between the sealant and the primer. If too much primer has been applied, a powdery, chalky, dusty film may form on the surface. Excess primer should be removed by (dusting the joint with a clean, dry, lint-free cloth or a non-metallic bristle brush). Allow the primer to dry. This normally takes about 10 to 15 minutes. The drying time will depend on the temperature, air-flow and humidity within the work area.

After the primer has dried, apply the sealant as normal, and in accordance with the data contained within the Technical Data Sheet for the primer. The use of a surface primer, although not mandatory an many cases, does increase sealant adhesion.

And don’t forget, we stock the entire range of Cox sealant guns. Try one of our combo packages, sealant, primer and gun. Details available upon request.